1. Field of the Invention
The present invention relates generally to spray boom systems for the purpose of applying fertilizers and pesticides on turf, golf courses and sports fields. Spray booms are typically mounted on the rear of a dedicated vehicle sprayer or tractor mounted sprayer. Spray boom systems are typically mounted less than 24 inches from the ground and can be 20 foot wide for turf spray applications.
2. Brief Description of Prior Art
One important consideration in the spray application of chemicals such as fertilizers and pesticides can be disturbance of the spray by factors such as wind. Gusts of wind can blow agricultural spray chemicals causing a variety of problems including the loss of expensive chemicals, misapplication of chemicals where they do not belong and health problems to the person applying the chemicals and even to people neighboring the application. For example, most spray applicator vehicles do not have a cab, so if the wind can carry the spray the operator is bound to be exposed to the wind borne spray during the application process. Also, golf courses which are a big user of ag chemicals are typically surrounded by expensive homes. To further the problem, many golf courses are built in areas such as coastal areas and islands that are prone to having high winds.
U.S. Pat. No. 5,431,341 shows a typical agricultural sprayer such as might be used on golf courses. The device exhibits a number of the problems with the prior art. For example, the device has brush shields 10 to limit wind blown spray however, the shields 10 blind the operator from being able to see the chemicals as applied. It is desirable for the operator to be able to see that the chemicals are actually being applied and how much, otherwise an operator can drive around with an empty tank believing they are spraying. The shields 10 are also applied with bolts. In this case, wing nuts allow for a somewhat quick mounting and release but wing nuts are prone to get lost. Bolts and wing nuts also corrode, making it a chore to install and remove the shields. This patent '341 uses castors to support the ends of the device. Castors cause further problems. Castors can jar the equipment when they hit a bump and on a golf course they can fall into the sand traps and cause ruts in soft ground. Because the operator cannot see the castors they have a tendency to run over things. Castors also track through the applied chemical and can transfer the chemicals to areas where they are not wanted. Castors further transmit vibration to spray booms causing premature failure. Another problem with the prior art and patent '341 is that the nozzles are unprotected and yet run close to the ground. It is common for nozzles and related plumbing that are unprotected like nozzle 20 to get bent or broken or fouled when the operator accidentally hits an obstacle or even when an operator purposely drives over something believing there is sufficient clearance. Another problem is the tendency to hit obstacles because the spray boom is so wide. Hitting an obstacle with the boom of patent '341 will most likely damage the boom and possibly cause a number of leaks. Because of the reliability problems and weight of the shields 10 they are sometimes removed from the equipment again, allowing wind to carry the chemical spray.
U.S. Pat. No. 6,491,234 addresses another problem with long sprayer booms which is the shock caused when the vehicle hits a bump. The long sprayer arms, if unsupported, tend to amplify each movement with a pendulum effect. Patent '234 uses conventional shock absorbers to absorb some of this movement and to dampen the pendulum effect. Patent '234 is limited to a telescoping boom without shields.
As will be seen from the subsequent description, the preferred embodiments of the present invention overcome the above problems and difficulties of the prior art.